Reaction Engines Preps For Proof-of-Concept Testing

Spaceplanes powered by Sabre engines could launch payloads more efficiently than rockets.

Reaction Engines is exhibiting at the Farnborough Airshow this year (Hall 4, Stand 4018) to update show visitors on progress toward testing its Synergetic Air-Breathing Rocket Engine (Sabre). It is one of the UK’s longest-running advanced technology projects and might eventually result in a lightweight reusable space launch vehicle that can operate from runways.

Reaction Engines was co-founded in 1989 by Alan Bond and two partners after the HOTOL (Horizontal Take Off and Landing) project foundered. The company refined its engine and launch vehicle designs over the following two decades, with support from private investors. The designs eventually gained technical endorsement from the European Space Agency (ESA) and the U.S. Air Force Research Laboratory (AFRL).

In 2013 the UK Space Agency agreed to provide a £61 million (US$80 million) grant of government money. In 2015, BAE Systems made a “strategic investment” of £21.6 million (US$28.4 million). Boeing, Rolls-Royce, and more private investors have since pitched in. Alan Bond retired last year, but the company’s headcount has grown from 30 to 200 in the past four years.

In a recent briefing, Robert Bond, the company’s head of propulsion, noted that launch vehicle technology had not changed much in more than 60 years. Rockets are still expensive and unreliable, he said. The new entrants—presumably a reference to Blue Origin and SpaceX—can achieve only moderate gains, he claimed.

Reaction Engines believes that the solution can found in Sabre, which operates in air-breathing mode from takeoff to Mach 5+, and then as a liquid-oxygen rocket to achieve orbital velocity of Mach 25+. Bond described this as “a breakthrough,” especially the lightweight heat exchanger that cools incoming air. The thrust-to-weight ratio of the Sabre engine is much greater than that of the ramjets and scramjets that have offered propulsion up to Mach 3.

Bond said that the core of Sabre is now being built, with testing expected to take place in 2020. The company began construction of an engine test facility at Westcott in the UK last year. In the meantime, it is running an old GE J79 jet engine at a test site in Colorado to verify the operation of the heat exchanger.

Bond showed various launch vehicle designs, with single- and two-stage-to-orbit options. The company’s own Skylon design was one, but with airframers BAE Systems and Boeing now being shareholders, the eventual spaceplane could look different.

The company’s ambition extends further than providing low-cost satellite launches. Bond noted that Sabre could enable level hypersonic flight at very high altitude–above 100 kilometers. That would permit a sensor-carrying airframe to perform reconnaissance missions over “denied areas” that can be legally imaged only from space today.

Dr. Robert Bond was speaking at the Defence Space Conference in London last May, organized by the MoD and the Air Power Association: www.airpower.org.uk.